blocking factor

Main Entry: blocking antibody
Function: noun
: an antibody that combines with an antigen without visible reaction but prevents another antibody from later combining withor producing its usual effect on that antigen called also incomplete antibody

blocking antibody n.

1. An antibody that combines with an antigen without a reaction but that blocks another antibody from later combining with that antigen.

2. An immunoglobulin that combines specifically with an atopic allergen but does not elicit an allergic reaction.